Messages in this thread | | | Date | Wed, 11 Dec 2002 14:18:20 +0000 | Subject | Re: [PATCH] dm.c - device-mapper I/O path fixes | From | Joe Thornber <> |
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On Wed, Dec 11, 2002 at 07:16:53AM -0600, Kevin Corry wrote: > However, it might be a good idea to consider how bio's keep track of errors. > When a bio is created, it is marked UPTODATE. Then, if any part of a bio > takes an error, the UPTODATE flag is turned off. When the whole bio > completes, if the UPTODATE flag is still on, there were no errors during the > i/o. Perhaps the "error" field in "struct dm_io" could be modified to use > this method of error tracking? Then we could change dec_pending() to be > something like: > > if (error) > clear_bit(DM_IO_UPTODATE, &io->error); > > with a "set_bit(DM_IO_UPTODATE, &ci.io->error);" in __bio_split().
The problem with this is you don't keep track of the specific error to later pass to bio_endio(io->bio...). I guess it all comes down to just how expensive that spin lock is; and since locking only occurs when there's an error I'm happy with things as they are.
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